Our overall goal is to develop an informatics infrastructure essential for supporting basic cancer genetics research using the mouse as a model system for human cancer. The Mouse Tumor Biology (MTB) Database (http://tumor.informatics.iax.org) has become a primary resource for researchers seeking integrated information on the frequency, incidence, genetics, and pathology of neoplastic disorders in mice. MTB emphasizes data on tumors that develop characteristically in different genetically defined strains of mice (inbred, mutant, and genetically engineered) that serve as disease models for human cancers. MTB provides data to assist in selection of strains for experimentation and is a platform for mining data on tumor development and patterns of metastases. We now propose to build on this resource. Specifically: [unreadable] We will improve MTB's coverage of data on genetic changes in tumors, by including a growing body of information on whole genome profiling of genetic and gene expression changes in tumors. [unreadable] We will develop tools for exploring chromosomal and sequence-based maps of cancer-associated susceptibility and modifier loci and somatic mutations that occur in tumors. [unreadable] We will continue to populate MTB with data on strain-specific patterns of tumorigenesis in inbred, mutant, and genetically engineered mice, including data on tumor diagnoses and histopathology images. [unreadable] We will support the infrastructure of MTB through database maintenance, development of new software components, user support services, and community outreach activities. Our objective is to provide the user with current data about mouse models for human cancer and provide tools for exploring and exploiting MTB data to inspire new hypotheses that may provide novel insights into the process of cancer initiation and progression. Relevance to Public Health: The Mouse Tumor Biology Database (MTB) is a publicly accessible internet resource that the scientific community uses to assist in selection of mouse strains that will serve as experimental models for human cancer. Researchers interrogate MTB for information on tumor incidence, data on genetic variants carried by strains, and on somatic changes that occur characteristically in specific cancers. Priority for data curation and representation in the database is given to those strains that serve as models for the predominant human cancers and those new strains developed specifically to reflect the human clinical disease. The expansion and visualization tools planned for MTB will further enhance the value of the mouse as a model system for understanding human biology and cancer processes.